Radioactive preparation.



E'Rhlllll GE IIIEDERSCHbNEWEIDE, NEAR BERLIN, GERMANY, ASSIG-NQR TO THE FIRM O)? KUNHEIM dc C0,, 03 BERLIN, GERMANY, AND THE FIRM ITIEBLGESELLSCHAFT, OF BERLIN, GERMANY.

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y ugsgyymj Specification of Letters Patent. "Pafigntgfl N'gnz, so, g Ito ITlrawlng. Application fiie i December 11, 1913. Serial No. 805,968.

To (ZZZ w ham it may concern:

Be it known that I, Enwsr Hnrnnnnnron, a citizen of the German Empire, residing at liiedersch(inewe-ide, near Berlin, many, have invented certain new and useful Improvements in Radioactive Preparations, of which the following is a specification.

This invention relates to a radioactive pre iauution comprising a block or receptaole of porous, substance carried by said block or receptacle. @bj'cct of? 1.8 invention isaradioactive preparation oi: this hind wherein thcradioactive substance carried by the inert, porous blocl: consists of a material which by spon taneous decomposition forms that kind of radioactive substance which is the mother substance of emanations that is to say the .ibstance which emits cmanations. The radioactive material which in accordance with this invention is preferably used in com .ion with an inert, solid, porous carrier is radiothorium. The first product of spontaneous decomposition oi this material is thorium-3i and the thorium-X. is the mother substance of the thorium emanation which formed on spontaneous decomposition. of thorium-X. he, duration or half d constant of the radio-thorium is about r years, halhperiod constant of the thrurnsl about four and. the halfperiod cor taut of the thorium-emanation y fifty-two seconds.

In order to obtain the new radioactive preparation the active substance having the property to pro by spontaneous decomposition. the mother substance of emanation, preferably radio-thorimm preferably is included in a receptacle of inert, porous ma-.

terial such ,aTlQSQlZl'lll'i", so that the rcceptacic prew 1 loss of the active substance. 3i cour it is not necessary that such, rcceptaclc is on all sides closed by inert, porous walls.

in order to make use of the new radioacrive preparation it is put into a liquid having the property to dissolve the mother substance of the estimation of the radioactive substance contained in'thc porous block but no to dissolve the radioactive substance of itself. Preferably the new radio- Gen.

inert material. and radioactive active preparation is arranged within the fluid receptacle in such a, manner that it bars its outletso that the fluid drawn off from the receptacle must penetrate through the radioactive porous block and thus obtains an opportunity to dissolve the soluble mot-her substance of the emanation which has been formed by spontaneous decomposition of the radioactive substance, and to carry it away. It appears from this that it is necessary in Order to allow proper use of the new radioactive preparation that the radioactive substance itself and its first prod not of spontaneous decomposition have different solubility. In the case of radiothorium as radioactive substance and of thorium-X as first product of dccomposi tiOn this condition is broadly fulfilled. suitable liquid in the case a so-called physiological common salt solution; by which is meant a very weal-r solution of sodium chlcrid either rendered slightly ah kaline, by sodium carbonate, or somew. at acidulated by hydrochloric acid.

I am aware that radioactive preparations are known which compi" a solid block of inert porous material containing; incorporated radioactive substances. The purpose of these known radioactiveprcparntions was to permit their emanation leave the solid block through its pores wherea the mother substance of the ci'nanation was intended to be retained within the body. The present invention relates to a special embodiment of such previously known radioactive preparations and is distinguished from some by this, that it does not aim at a separation of the emanation from its mother substance and retaining the latter within the inert porous block but that it aims at a. separation of the mother substance of the emunution fromthe block and retaining the radioactive substance which produces the mother substance of the emanation within the block.

What I claim is:-- I F 1. A radioactive preparation comprising a solid body of inert, porous material and a radioactive substance carried thereby,

A radioactive "preparation consisting of a porous block of inert material containing inclosed therein radio'thorium.

-3. A radioactive preparation consisting of a block of kieselguhr having a cavity containing radio-thorium.

l. A radioactive solid block containing radio-tliorium incor 'iorated in inert porous material, said block arranged Within a re ceptacle containing a liquid adapted to dissolve the tliori'mn-X formed by self-decomposition of said radio-thorium but not to dissolve radio-thorium.

A radioactive solid block containing radio-thorium incorporated in inert porous aser/o4 material, said block arranged Within a receptacle containing a physiological common salt solution.

6. A radioactive solid block containing radio-thorium incorporated in inert porous material, said block arranged Within a receptacle containing an acidulated weak so lution of common salt.

In testimony whereof 1 afiix my signature Witnesses HENRY HASPER, WOLDEMAR HAUPT. 

